The transmission channels of subscriber line interface circuits, or SLICs, employed by telecommunication service providers include a very demanding set of performance requirements including accuracy, linearity, insensitivity to common mode signals, low power consumption, low noise, filtering, and ease of impedance matching programmability, to facilitate interfacing the SLIC with a variety of telecommunication circuits including those providing digital codec functionality. In a typical application, the length of the wireline pair to which a SLIC is connected can be expected to vary from installation to installation, may have a very significant length (e.g., on the order of multiple miles), and transports both substantial DC voltages, as well as AC signals (e.g., voice and/or ringing). As a consequence, it has been difficult to realize a SLIC implementation that has ‘universal’ use in both legacy and state of the art installations.